PSI - Issue 84

Valentina Giglioni et al. / Procedia Structural Integrity 84 (2026) 481–488

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natural frequencies, is extracted, providing a rich and diverse description of the structural dynamic response. The target model consists of a second Finite Element Model (FEM) of the same bridge, developed in Abaqus (Dassault Systèmes Simulia Corp., 2020) and characterized by a higher level of modelling accuracy. While the target domain is intended to act as a proxy for the real structure, the source domain represents a simplified archetypal FEM, designed to efficiently generate many labeled monitoring scenarios. Future work will focus on evaluating the TL performance of the proposed methodology, with the aim of identifying the most effective DANN among those developed in parallel, i.e., the model best capable of correctly classifying that

specific damage scenario in the target domain. 2. Description of source and target bridges

The SHM strategy is here applied to a case study which is a numerical replica inspired by an in-service roadway bridge, located in Toscana, Italy, representative of many bridges managed by ANAS Spa. The post-tensioned reinforced concrete bridge consists of simply supported spans, each 45 m long. The deck cross-section is composed of four longitudinal double-T girders connected by three transverse beams and a rectangular concrete slab. Each span is supported by two piers located at its ends. In the absence of experimental monitoring data, a high-fidelity finite element model is constructed in the Abaqus environment to closely replicate the real structure. As illustrated in Fig. 1, the deck and pier caps are represented using solid elements to capture the realistic geometry and joint configuration, whereas the piers are modelled with beam elements by assigning the actual cross-sectional properties to the corresponding generalized beam sections. The bridge is equipped with a post-tensioning system consisting of seven tendons per girder, which are not modelled individually but replaced by an equivalent tendon, represented by wire elements with an embedded region constraint.

Fig. 1. General view of the solid model of the case study bridge in the ABAQUS environment

To define the source domain and generate a comprehensive labelled dataset, a simplified archetypal finite element model of the same bridge is developed. This secondary FEM is implemented in the SAP environment, where beam elements are adopted to represent all structural components, except for the slab, which is modelled using shell elements. The connections between adjacent spans are simulated through rigid links combined with six-degree-of freedom (6-DOF) spring elements. To further simplify the model and distinguish it from the high-fidelity counterpart, the prestressing effect of the seven tendons is represented by an equivalent uniformly distributed load, computed according to Eq. (1). , =∑ 8 2 7 =1 (1)